U.S. Pat. No. 4,953,761, which is incorporated herein by reference in its entirety, discloses a stopper rod spatial control mechanism that is used to control the gravity flow of a molten metal through a nozzle. Alignment of the stopper rod with the nozzle in the disclosed mechanism is achieved by rotating the boom of the mechanism about the defined longitudinal axis Y-Y and swinging the boom about the defined longitudinal axis Y′-Y′, which is offset from the Y-Y axis. While this arrangement provides a satisfactory method of adjustment, accomplishing the alignment via the rotational moment arm established between the offset pair of axes has disadvantages.
It is one object of the present invention to provide a stopper rod positioning and control apparatus that has at least one method of precision alignment of the stopper rod with the nozzle that is achieved about a single longitudinal axis with no rotational moment arm. It is another object of the present invention to provide additional methods of precision alignment of the stopper rod with the nozzle that can be achieved in combination with a method of precision alignment of the stopper rod with the nozzle that is achieved about a single longitudinal axis.
It is another object of the present invention to provide at least two stopper rod positioning and control apparatus that have at least one method of precision alignment of the stopper rod with the nozzle that is achieved about a single longitudinal axis with no rotational moment arm, and are used to control the flow of molten metal through multiple nozzles situated in a common reservoir of molten metal.